54 Mr. Elliott Coues on Picicorvus colurabianus, 



Chicago Acad. 1869, p. 286), mentioning a specimen collected at 

 Sitka by BischoflF. In the other direction we have no Mexican 

 quotations to my knowledge; nor is the species noticed in 

 the Mexican Boundary Survey : but this evidence is only nega- 

 tive ; and, from what is known of some corresponding cases, I 

 should not like to affirm that the bird may not pass to the 

 south of the United States, along certain high lines where de- 

 crease of latitude is compensated for by increase of altitude. 

 Still our positive evidence goes far towards fixing the limit 

 somewhere about 34° N. We may cite the following as refer- 

 ences approximating towards this parallel : — Mimbres to Rio 

 Grande, T. C. Henry (see Baird, B. N. A. 1858, 573) ; Can- 

 ton, Burgwyn, N. M., W. W. Anderson (Baird, op. cit. 925) ; 

 75 miles west of Albuquerque, N. M., C. B. R. Keunerly (Pac. 

 R. R. Rep. X. 1859, iv. 32) ; Fort Whipple, Ariz., Coues (Pr. 

 A. Sc. Philad. 1866, 55) ; Fort Tejon, Col. J. Xantus (see 

 Coop. Cal. Birds, i. 298). To the eastward, darkens Crow has 

 been found by Dr. Cooper in Nebraska, near Fort Kearney, 

 which lies in long. 99° 6' W. (Greenw.), about 3000 feet above 

 sea-level, and by Dr. Suckley on Milk River, in the same State, 

 200 miles east of the Rocky Mountains. These are probably 

 extreme instances. In mentioning above a westward extent 

 " to the Pacific" I must not be taken literally (for I do not 

 know that the bird ever comes down to the sea-level), but as 

 meaning that it inhabits the mountains west of the main chain — 

 namely, the Sierra Nevadas of California, the Cascade Mountains 

 of Oregon, and, finally, the coast-range of both these countries. 

 We have thus circumscribed the range of darkens Crow with 

 probably a close approximation to accuracy ; but it is not the 

 fact that the bird actually inhabits all the area within the 

 salient points indicated. Such is not the case ; and this brings 

 us to the matter of its distribution according to altitude. To 

 begin at the top, we find Picicorvus as high up the mountains 

 as probably any bird goes, not even excepting Lagopus leucurus. 

 " While crossing the Cascade Mountains," says Dr. Newberry 

 (P. R. R. Rep. vi. 1857, pt. iv. p. 83), "at the line of perpetual 

 snow, 7000 feet above the sea-level, I have seen this bird, with 

 Lewis's Woodpecker [Melanerpes torquaius), flying over the snow- 



